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10/12/2018, 4:21 am EDT

Global Soil Moisture Observation/Forecast Trend

Past 3 months: DRAMATIC drying of global soil moisture Next 3 months: El Nino brings balance in wetter/drier regions Fig. 1: September 2018 global soil moisture % of normal and 3-month trend. Observation discussion: SHOCKING is the number of dry trend areas versus wet over the past 3 months. In North America strong drought intensified across Western Canada and Quebec while wet soils in Alaska have eased. Dryness strengthened over the West U.S. while one of the few global wet changes during the past quarter year was observed in the Midwest to Mid-Atlantic U.S. The Caribbean region to Central America and Mexico are much drier. In South America there were minor changes but only wetter central South America and a drier pattern across Chile were notable. The European drought spread across Central Europe and intensified. Dryness in the Black and Caspian Sea regions also evolved. Interestingly, West Africa including the Western Sahara was wetter. Northern and Central Russia were drier while much of China trended wetter during the last 3 months. Dryness evolved over India and Southeast Asia while Australian drought intensified. The number of drier regions outnumbered the number of wetter regions by 18 to 4. Fig. 2: September 2018 global soil moisture % of 30-year normal and 3-month forecast. Forecast discussion: The outlook is based primarily on an ENSO analog which features El Nino onset but is biased toward most of the energy produced by East Pacific warming of the ocean biased toward the Dateline rather than a strong conventional El Nino. The outlook indicates a more balanced result with about one dozen drier and wetter regions. In North America typical wetter conditions caused by El Nino are forecast from Texas to the Southeast U.S. But usually wetter California during El Nino is drier caused by the El Nino warming shifted westward toward the Dateline. Therefore California drought may worsen, unusual for an El Nino winter. Farther north the Ohio Valley to Quebec is drier. Much needed stormy winter is forecast for southwest Canada where dry conditions exist. In South America the classic El Nino-signature occurs: Dryness in Brazil and wet weather centered on Uruguay. South and southwest Africa dryness widens. East Africa to Mozambique wet conditions strengthen. To the north across Europe the drought in U.K. to France and Germany eases. Italy to Greece turns much drier. Parts of the Black Sea region turn wetter although Western Russia soil moisture should remain about the same. A drought east and southeast of the Caspian Sea is forecast to fade. A large area of wetter conditions are likely across north and northeast Russia caused by a storm track made wetter by open ocean (no ice) enabling the storm track to gain snowier systems. Wetter conditions are forecast from Japan to eastern China to Southeast Asia. Western Indonesia is wetter while eastern sections are drier. Widespread dryness is indicated in Australia. However, the profound dry forecast making Australian drought worse could be a little wetter in central sections if the +IOD forecast fails.